In recent years, machines have been required to attain long lives and be maintenance free. As a result, rolling bearings used for such machines are also required to attain a long rolling fatigue life. In order to attain a long rolling fatigue life, it is considered to change a material of a bearing part (a ring member and a rolling element), which is a part of such a rolling bearing. Specifically, steel, which is a representative material of the bearing part, is provided with an alloy component effective to attain a long life, thereby attaining a long rolling fatigue life.
However, if a special material is employed for the material of the bearing part, it may be difficult to acquire the material depending on locations of manufacturing bases in view of a current circumstance that the manufacturing bases are spreading across the globe. In view of such a circumstance, it is not necessarily preferable to employ a special material so as to attain a long rolling fatigue life.
As an alternative measure for attaining a long rolling fatigue life, there has been proposed to attain long lives of a bearing part and a rolling bearing by means of heat treatment (for example, see Japanese Patent Laying-Open No. 7-190072 (Patent Document 1), Japanese Patent Laying-Open No. 2003-226918 (Patent Document 2), and Japanese Patent Laying-Open No. 2000-161363 (Patent Document 3)).